diff --git a/source/lib/SihnonFramework/Exceptions.class.php b/source/lib/SihnonFramework/Exceptions.class.php
index 241ee73..429267a 100644
--- a/source/lib/SihnonFramework/Exceptions.class.php
+++ b/source/lib/SihnonFramework/Exceptions.class.php
@@ -8,6 +8,12 @@ class SihnonFramework_Exception_AlreadyInitialisted    extends SihnonFramework_E
 class SihnonFramework_Exception_NotImplemented         extends SihnonFramework_Exception {};
 class SihnonFramework_Exception_MissingDefinition      extends SihnonFramework_Exception {};
 
+class SihnonFramework_Exception_TemplateException      extends SihnonFramework_Exception {};
+class SihnonFramework_Exception_AbortEntirePage        extends SihnonFramework_Exception_TemplateException {}; 
+class SihnonFramework_Exception_Unauthorized           extends SihnonFramework_Exception_TemplateException {};
+class SihnonFramework_Exception_FileNotFound           extends SihnonFramework_Exception_TemplateException {};
+class SihnonFramework_Exception_InvalidParameters      extends SihnonFramework_Exception_TemplateException {};
+
 class SihnonFramework_Exception_DatabaseException      extends SihnonFramework_Exception {};
 class SihnonFramework_Exception_DatabaseConfigMissing  extends SihnonFramework_Exception_DatabaseException {};
 class SihnonFramework_Exception_DatabaseConnectFailed  extends SihnonFramework_Exception_DatabaseException {};
@@ -24,6 +30,5 @@ class SihnonFramework_Exception_CacheObjectNotFound    extends SihnonFramework_E
 
 class SihnonFramework_Exception_InvalidPluginName      extends SihnonFramework_Exception {};
 
-class SihnonFramework_Exception_FileNotFound           extends SihnonFramework_Exception {};
 
 ?>
diff --git a/source/lib/SihnonFramework/Main.class.php b/source/lib/SihnonFramework/Main.class.php
index c0b7d1e..5f28891 100644
--- a/source/lib/SihnonFramework/Main.class.php
+++ b/source/lib/SihnonFramework/Main.class.php
@@ -116,7 +116,10 @@ class SihnonFramework_Main {
             if (preg_match("/^{$class['base']}_/", $classname)) {
                 // Special case: all related exceptions are grouped into a single file
                 if (preg_match("/^({$class['base']}_(?:.*?_)?)Exception/", $classname, $matches)) {
-                    require_once($class['base_dir_prefix'] . preg_replace('/_/', '/', $matches[1]) . 'Exceptions.class.php');
+                    $exceptions_filename = $class['base_dir_prefix'] . preg_replace('/_/', '/', $matches[1]) . 'Exceptions.class.php';
+                    if (file_exists($exceptions_filename)) {
+                        require_once($exceptions_filename);
+                    }
                     return;
                 }
                     
@@ -231,7 +234,7 @@ class SihnonFramework_Main {
             return $var;
         }
         
-        if (is_string($default) && preg_match('/^Sihnon(Framework)?_Exception/', $default) && class_exists($default) && is_subclass_of($default, SihnonFramework_Exception)) {
+        if (is_string($default) && preg_match('/^Sihnon(Framework)?_Exception/', $default) && class_exists($default) && is_subclass_of($default, 'SihnonFramework_Exception')) {
             throw new $default();
         }
         
diff --git a/source/lib/SihnonFramework/PluginFactory.class.php b/source/lib/SihnonFramework/PluginFactory.class.php
index 4598d6d..5c55b7c 100644
--- a/source/lib/SihnonFramework/PluginFactory.class.php
+++ b/source/lib/SihnonFramework/PluginFactory.class.php
@@ -36,7 +36,7 @@ abstract class SihnonFramework_PluginFactory implements Sihnon_IPluginFactory {
         $plugins = array();
         
         if (! is_array($directories)) {
-            $directories = array(SihnonLib => $directories);
+            $directories = array(Sihnon_Lib => $directories);
         }
         
         foreach ($directories as $base_dir => $directory) {
@@ -87,4 +87,4 @@ abstract class SihnonFramework_PluginFactory implements Sihnon_IPluginFactory {
     
 }
 
-?>
\ No newline at end of file
+?>
diff --git a/source/lib/SihnonFramework/RequestParser.class.php b/source/lib/SihnonFramework/RequestParser.class.php
index c37613a..95b64fa 100644
--- a/source/lib/SihnonFramework/RequestParser.class.php
+++ b/source/lib/SihnonFramework/RequestParser.class.php
@@ -73,7 +73,7 @@ class SihnonFramework_RequestParser {
     }
 
     public function exists($key) {
-        return isset($this->vars[$key]);
+        return array_key_exists($key, $this->vars);
     }
 
     public function get($key, $default = null) {
@@ -81,7 +81,7 @@ class SihnonFramework_RequestParser {
             return $this->vars[$key];
         }
         
-        if (is_string($default) && preg_match('/^[a-zA-Z_]+_Exception/', $default) && class_exists($default) && is_subclass_of($default, SihnonFramework_Exception)) {
+        if (is_string($default) && preg_match('/^[a-zA-Z_]+_Exception/', $default) && class_exists($default) && is_subclass_of($default, 'SihnonFramework_Exception')) {
             throw new $default();
         }